Field of the Invention
The present invention relates to an ion-exchange equipment for removing impurity ion contained in a cooling liquid in a fuel cell system, for example.
Description of the Related Art
In a conventional technology concerning a fuel cell system, in order to cool a fuel cell that generates heat according to power generation, a cooling circuit is provided for forcibly circulating a cooling liquid by operating a pump. In such cooling circuit, there may cause a case of generating rust or like in the cooling circuit because of circulation of the cooling liquid, and as a result, impurity ion may be generated in the cooling liquid by such rust or by splitting reaction of the cooling liquid.
Further, it is known that such impurity ion raises electric conductivity of the cooling liquid, which may lead to such a problem as that electricity generated by the fuel cell leaks externally through the cooling liquid, and hence, power generation efficiency is decreased. In order to obviate such problem, an ion-exchange equipment is provided in a cooling circuit of a fuel cell system for removing the impurity ion in the cooling liquid.
For removing such impurity ion, an ion-exchange resin fills an interior of such ion-exchange equipment, and the impurity ion in the cooling liquid is removed by passing the cooling liquid through the ion-exchange resin.
Further, since the ion-exchange resin does not move within the ion-exchange equipment, the cooling liquid hardly flows through the ion-exchange resin filling corner portions of the ion-exchanger equipment, which prohibits smooth and efficient ion-exchanging operation, thus being inconvenient.
In order to solve such problem or inconvenience mentioned above, known art provides a method, as disclosed in the Patent Document 1 (Japanese Patent Laid-open No. 8-164386), in which an ion-exchange resin is agitated or stirred inside the ion-exchange equipment to make even distribution of the ion-exchange resin within the ion-exchange equipment to thereby efficiently perform the removal of the impurity ion till expiration of date for use of the ion-exchange resin.
The ion-exchange equipment disclosed in the Patent Document 1 is equipped with a softening (demineralizing) tank provided with a liquid flow-in port (supply port) formed to a lower portion thereof and a liquid flow-out port (discharge port) formed to an upper portion thereof, an ion-exchange resin filling the softening tank, and a floating plate disposed between the liquid flow-in port and the liquid flow-out port of the softening tank and the ion-exchange resin, the floating plate being formed with a number of pores having a pore diameter smaller than a particle diameter of the ion-exchange resin.
According to the ion-exchange equipment of the Patent Document 1 having the structure mentioned above, when raw water is supplied into the softening tank while raising the floating plate by water flow of the raw water, the raw water is jetted through the pores of the floating plate, and hence, the ion-exchange resin is also blown upward and agitated into coagulated columnar form. As a result, the ion-exchange resin becomes entirely usable for the softening of the raw water.
However, according to the structure of the Patent Document 1, the floating plate is moved up and down inside the softening tank, there may cause a case in which abnormal noise is generated and the floating plate is damaged by abrasion. More specifically, when a fuel cell provided with such ion-exchange equipment is mounted to an automobile, a fear of strength poverty in structure is considered by vibration during running of the automobile.
In addition, in a conventional ion-exchange equipment mounted on an automobile, since the ion-exchange resin fills a softening tank by applying pressure, it is difficult for cooling liquid to flow smoothly and to avoid increase of pressure loss. Therefore, a fear that high load is applied to a pump for circulating the cooling liquid has been considered.